26,098 papers · page 368 of 1,305
SLP Auto-vectorization converts straight-line code into vector code. It scans input code for groups of instructions that can be combined into vectors and replaces them with their corresponding vector instructions. This work introduces Super-Node SLP (SN-SLP), a new SLP-style algo…
Inlining is one of the most important compiler optimizations. It reduces call overheads and widens the scope of other optimizations. But, inlining is somewhat of a black art of an optimizing compiler, and was characterized as a computationally intractable problem. Intricate heuri…
Optimizing data-intensive applications such as image processing for GPU targets with complex memory hierarchies requires to explore the tradeoffs among locality, parallelism, and computation. Loop fusion as one of the classical optimization techniques has been proven effective to…
Resource-constrained devices for embedded systems are becoming increasingly important. In such systems, memory is highly restrictive, making code size in most cases even more important than performance. Compared to more traditional platforms, memory is a larger part of the cost a…
This paper presents a technique to generate in-bounds inputs for arrays used in memory-unsafe programming languages, such as C and C++. We show that most memory indexation found in actual C programs follows patterns that are easy to analyze statically. Based on this observation, …
With the popularity of Node.js, asynchronous, event-driven programming has become widespread in server-side applications. While conceptually simple, event-based programming can be tedious and error-prone. The complex semantics of the Node.js event loop, coupled with the different…
We discuss the design and the implementation of Locus, a system and a language to orchestrate the optimization of applications. The increasing complexity of machines and the large space of program variants, produced by the many transformations available, conspire to make compiler…
The throughput of B+ tree query processing is critical to many databases, file systems, and cloud applications. Based on bulk synchronous parallel (BSP), latch-free B+ tree query processing has shown promise by processing queries in small batches and avoiding the use of locks. As…
RNA-RNA (Ribo-Nucleic Acid) Interactions (RRI) has led to significant successes in Cancer treatment. However, programs that model these interactions are computationally and memory intensive: for sequences of lengths N and M, space is Θ(N2M2), and the time is Θ(N3M3). Conducting g…
We present Janus, a framework that addresses the challenge of automatic binary parallelisation. Janus uses same-ISA dynamic binary modification to optimise application binaries, controlled by static analysis with judicious use of software speculation and runtime checks that ensur…
Architectures for High-Performance Computing (HPC) now commonly employ accelerators such as Graphics Processing Units (GPUs). High-level programming abstractions for accelerated computing include OpenMP as well as RAJA and Kokkos—programming abstractions based on C++ templates. S…
We formalise the computational undecidability of validity, satisfiability, and provability of first-order formulas following a synthetic approach based on the computation native to Coq's constructive type theory. Concretely, we consider Tarski and Kripke semantics as well as clas…
In this article, we provide a Coq mechanised, executable, formal semantics for a realistic fragment of SQL consisting of "select [distinct] from where group by having" queries with null values, functions, aggregates, quantifiers and nested potentially correlated sub-queries. Rely…
IsaFoL (Isabelle Formalization of Logic) is an undertaking that aims at developing formal theories about logics, proof systems, and automatic provers, using Isabelle/HOL. At the heart of the project is the conviction that proof assistants have become mature enough to actually hel…
The insertion of expressions mixing arithmetic operators and bitwise boolean operators is a widespread protection of sensitive data in source programs. This recent advanced obfuscation technique is one of the less studied among program obfuscations even if it is commonly found in…
When presented with a formula to prove, most theorem provers for classical first-order logic process that formula following several steps, one of which is commonly called skolemization. That process eliminates quantifier alternation within formulas by extending the language of th…
Linear recurrences with constant coefficients are an interesting class of recurrence equations that can be solved explicitly. The most famous example are certainly the Fibonacci numbers with the equation f(n) = f(n−1) + f(n−2) and the quite non-obvious closed form 1 √ 5 (ϕn − (−ϕ…
It is well known that (ground) confluence is a decidable property of ground term rewrite systems, and that this extends to larger classes. Here we present a formally verified ground confluence checker for linear, variable-separated rewrite systems. To this end, we formalize proce…
We present a linear logical framework implemented within the Hybrid system [Felty and Momigliano 2012]. Hybrid is designed to support the use of higher-order abstract syntax for representing and reasoning about formal systems, implemented in the Coq Proof Assistant. In this work,…
We formally prove the undecidability of entailment in intuitionistic linear logic in Coq. We reduce the Post correspondence problem (PCP) via binary stack machines and Minsky machines to intuitionistic linear logic. The reductions rely on several technically involved formalisatio…